A police officer pepper sprays a protester as another protester stands in front of the race director's car during stage 16.
REUTERS/Stephane Mahe

BAGNERES-DE-LUCHON, France (Reuters) - A protest by local farmers brought stage 16 of the Tour de France to a halt on Tuesday as bales of hay were thrown on to the road on the route from Carcassonne to Bagneres-de-Luchon and police tear gas blew into the faces of some of the riders.

The gas was used to disperse the protesters but it ended up blowing in the direction of the peloton, which led to the race being stopped at the 187 km-to-go point.

A Reuters picture showed a police officer spraying an isolated demonstrator with what appears to be pepper spray while she was sitting on the ground.

The race continued after the brief hiatus.

Yellow jersey holder Geraint Thomas and world champion Peter Sagan were among the riders rinsing their eyes as the stage was stopped for 15 minutes.

It is not the first time that protesters have interrupted a prominent race, the most memorable incident happening in the 1984 Paris-Nice, when French great Bernard Hinault punched one of the demonstrators.

The last time a Tour stage was blocked by a demonstration was in 2004.

Local authorities said in a statement that an investigation into the incidents had been opened.